Boundary Atlas

ZIP code 57720: Buffalo, SD

ZIP code 57720 is in Buffalo (46% of residents), in Harding County, South Dakota. 54% of its residents live outside city limits. It is in South Dakota's at-large congressional district. Its state senate district is State Senate District 28; its state house district is State House District 28B.

752residents (2020 Census)
1,296.2 sq miland area
1cities and towns
1congressional district
6voting precincts

See it on the mapAll of South Dakota

City and county

City or townShare of ZIP residents
Buffalo46%

CountyShare of ZIP residents
Harding County100%

Town or county subdivisionShare of ZIP residents
Buffalo town46%
North Harding UT35%
South Harding UT19%

Congressional district

Congressional districtShare of ZIP residents
South Dakota's at-large congressional district (SD-AL)100%

State legislative districts

State senate districtShare of ZIP residents
State Senate District 28100%

State house districtShare of ZIP residents
State House District 28B100%

Voting precincts

6 voting precincts overlap ZIP 57720. Map them, with each precinct's share of the ZIP's residents.

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Your agent can get these cities, counties, districts and precincts with their shares, and their GeoJSON boundaries, from Boundary Atlas. Add https://atlas-production-d344.up.railway.app/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:

related_geographies(id="us:zcta:57720")

ZIP 57720 here is the Census Bureau's ZIP Code Tabulation Area, which approximates the USPS ZIP Code; PO-box-only ZIPs have none. Districts are the maps in force for the November 3, 2026 election.